2024-09-04

wonjunYou/BFS/PRG_도넛과_막대_그래프.py

@@ -0,0 +1,52 @@
+from collections import deque
+
+def solution(edges):
+    MAX_NUMBER = 1000001
+
+    start = [[] for _ in range(MAX_NUMBER)]
+    end = [[] for _ in range(MAX_NUMBER)]
+    visited = [False] * (MAX_NUMBER)
+
+    result = [0, 0, 0, 0]
+
+    for a, b in edges:
+        start[a].append(b)
+        end[b].append(a)
+
+    middle = -1
+    for node in range(MAX_NUMBER + 1):
+        if (len(end[node]) == 0 and len(start[node]) >= 2):
+            middle = node
+            break
+
+    result[0] = middle
+
+    def bfs(i):
+        q = deque()
+        q.append(i)
+
+        visited[i] = True
+
+        while q:
+            node = q.popleft()
+
+            if len(start[node]) == 2 and len(end[node]) == 2:
+                result[3] += 1
+                return
+
+            if not start[node]:
+                result[2] += 1
+                return
+
+            for next_node in start[node]:
+                if not visited[next_node]:
+                    visited[next_node] = 1
+                    q.append(next_node)
+
+        result[1] += 1
+
+    for node in start[middle]:
+        end[node].remove(middle)
+        bfs(node)
+
+    return result